Forms for printed circuit use or the like



May 22, 1962 A. FROHBACH 3,035,690

FORMS FOR PRINTED CIRCUIT USE OR THE LIKE Filed June 28, 1961 F|G.1FIG-2 F|G.3 l2 r r z N a .2

98 3,3 A 42 FIG. 9

INVENTOR.

LOUIS A. FROH BACH AGENT.

United States Patent 3,035,690 FORMS FOR PRINTED CIRCUIT USE OR THE LIKELouis A. Frohbach, Florence, Mass, assignor to (ghart- Pak, Inc., Leeds,Mass, a corporation of Connecticut Filed June 28, 1961, Ser. No. 120,345Claims. o1. 206-56) This invention relates to forms for printed circuituse or the like and means for dispensing such forms.

In providing what has been termed printed circuits. it is necessary tofurnish layouts of electrical wiring on an enlarged scale, which layoutssubsequently are reduced photographically. One of the importantrequirements is that the layout be sharp, of contrasting color, and ofprecise dimensions.

In order to avoid tedious and repetitious drawing and inking of eyelets,junction points, connector attaching areas and so forth, die out forms(the word form being used hereafter as a generic term) of various sizesand shapes have become available, which have been termed sometimes alsopads, pieces, etc. Each such form is coated on one side with a pressuresensitive adhesive layer for adhesion to the layout or drawing. Mostforms are made of a paper type material, of dark or black color so as topresent a good contrast to the camera and most commonly, are die-cut toexhibit sharp edges and be accurate in size. Typical forms available arefor instance, elbows, ovals, double end teardrops, circles, annuli, etc.

Forms supplied commercially for preparing such drawings are furnishedusually with their adhesive underside affixed to a temporary card or toa rolled strip from which the forms are removed one by one and then, bythe use of tweezers or one or two hands, located above the correct spotof the drawing surface or layout sheet. Next, the form is aflixed to thesurface by applying relatively light pressure.

It will be apparent therefore, that one or more forms are attached withtheir adhesive underside to a temporary surface, that the forms must belifted off such surface and subsequently must be re-afiixed to the finaldrawing or layout. In stripping off a form from the temporary storagesurface, manipulating the rather flimsy and adhesively coated form andin re-affixing the form, it is a common occurrence to damage the form,causing either wrinkles or tears which impair the final quality andaccuracy of the completed drawing. Also, the manipulating of flimsyforms is quite disconcerting to the user.

The present invention overcomes the above described short-comings byproviding forms so fastened to sheets or tapes, that the forms can beaccurately positioned on the drawing or layout surface and directlyafilxed thereupon without intermediate manipulation. In this Way,dimensional accuracy is maintained and no tools or instruments of anytype are required or employed. The transfer of forms from a storagesurface to the final drawing therefore, is a one-step operation, thusenhancing the accuracy and appearance of the circuit layout as well assimplifying the steps of making such printed circuit drawings.

One of the objects of this invention therefore is the provision of formsfor printed circuit use, avoiding one or more of the limitations anddisadvantages of prior art devices.

Another object of this invention is the provision of forms for printedcircuit use which forms are mounted in such a manner as to enabletransfer thereof directly to the final surface without intermediatemanipulation or use of instruments.

Another object of this invention is the provision of a supply of formsfor printed circuit use which forms are affixed in a new and novelmanner to sheet or tape material.

3,035,690 Patented May 22, 1962 A further object of this invention isthe provision of adhesively coated forms for printed circuit use whichforms are dispensable from a roll directly upon the final drawingsurface and whereby the forms remain adhesively aflixed to such surface.

A still further object of this invention is the provision of adhesivelycoated forms for printed circuit use whereby the forms are mounted in amanner as to remain dimensionally stable during use thereof.

Further and still other objects of this invention will be apparent fromthe following description when taken in conjunction with theaccompanying drawings in which:

FIGURE 1 is a side view of a roll of tape provided with typical forms;

FIGURE 2 is a top view at a portion of the tape provided with suchforms;

FIGURE 3 is a longitudinal section through a portion of the tape;

FIGURE 4 is a plan view of a drawing surface with forms aifixed thereto;

FIGURE 5 is a side view illustrating the preferred method oftransferring the forms from the tape to the drawing surface;

FIGURE 6 is a side view of an alternative construction of a roll of tapeprovided with forms;

FIGURE 7 is an enlarged longitudinal view of the alternativeconstruction per FIGURE 6;

FIGURE 8 is a top view of the roll of tape shown in FIGURE 6; and,

FIGURE 9 is a side view of a still further alternative construction.

Referring now to the figures and FIGURES 1 to 3 in particular, numeral11 identifies a roll of tape which roll is formed by two superposedtapes or strips of material,

numerals 12 and 13.

Tape 12, in a typical embodiment, is black crepe paper which at itsunderside is coated with a layer 14 of pressure sensitive adhesivematerial. The lower tape 13 is made of a material which will not adhereto any substantial degree to the adhesive coating 14, thus providingprotection for the adhesive coating. Typical non-adhering materialsuitable for this purpose is a silicon coated release paper.

At regular intervals along tape 12 there are provided forms for printedcircuit use, such as annular forms 15 which are produced by respectivedie-cut severance lines 16 in the tape material 12. These severancelines are of such depth and width in the tape that the annular forms areseparated from the surrounding tape material, yet remain located thereinby virtue of friction and the retention of the adhesive coating untilsuch time that the forms are adhesively afiixed to the drawing or layoutsurface.

FIGURE 4 shows a typical layout or drafting surface, usually a clear,transparent plastic sheet 21 incorporating grid lines for locatingpurposes. Two annular forms 15 are shown as affixed to the surface. Inorder to aid locating the center of the annular forms on the grid, asmall circular portion has been cut out from the center of each form asclearly seen in FIGURES 2, 3 and 4.

The dispensing of the forms and aiiixing thereof to surface 21 isillustrated in FIGURE 5. The roll of tape is held in the palm of onehand, the lower release tape 13 is folded back and the free end of tape12 is grasped by fingers of the other hand. A portion of tape with aselected form then is positioned accurately above surface 21, brought incontact therewith and the selected form pressed upon the selected partof surface 21. Tlds aflixes the form to the surface. Next, the free endof the tape and the roll are lifted from this particular spot on thesurface whereby the form separates itself along severance line 16 fromthe surrounding tape material, while the form remains adhesively afixedto the surface. For the sake of showing the roll of tape clearly, thethumb in FIGURE 5 is depicted as supporting the roll from underneath,although in practice it will be found that the thumb is placed mostconveniently across the center of the .roll.

As described hereinbefore, the form is transferred directly upon thefinal drawing or layout surface without intermediate handling, therebyimproving accuracy and speed, and leaving the form itself free fromdistortion and wrinkling. The form which is quite flimsy, remains fullysupported along its borders until it is affixed to the final surfacewhich then retains all portions thereof securely.

In the event that top surface of tape 12 has relatively little adhesionwith adhesive coating 14, tape 13 may be omitted from the roll 11.

Without deviating from the features described heretofore, it willreadily be understood by those skilled in the art that, instead ofannuli, other configurations may be provided, and that instead of rollsof tape, flat sheet material may be used, each sheet carrying one ormore such forms.

FIGURES 6 to 8 show a further embodiment of the invention and illustratean alternattive construction. Roll 31 is formed by two superposed layers32 and 33 of tape material. Material 32 is a clear transparent tape, forinstance a cellophane material, which is coated along its undersidecompletely or partially, for instance in a zonal pattern, with a layerof pressure sensitive adhesive material 35. At certain intervals alongthe tape, there are spaced from one another annular forms 37, which inturn are provided along their respective undersides with a coating ofpressure sensitive adhesive material 38. The top sides of the formsadhere completely or with portions thereof to the adhesive material 35so that the forms are held to the underside of strip 32.

The underside of the forms and particularly the pressure sensitivecoating thereof is protected by tape 33 which is material same orsimilar to tape 13, FIGURE 1. This tape is folded back during dispensingof forms.

By virtue of the transparency of tape 32, the forms are clearly visibletherethrou-gh and this tape can be brought into alignment with aselected spot on layout surface 21 as indicated in FIGURE 5. Uponexerting light finger pressure on a form through the top tape 32, therespective form is adhesively affixed to the layout form. Uponsubsequent removal of the tape from the respective spot, the formseparates from the underside of tape 32 while remaining adhesivelyaflixed however, to surface 21.

In order to accomplish this separation successfully, it is necessary toselect tape 32, the adhesive coating 35 and its area or zone ofapplication in conjunction with the form material in such a manner thatthe adhesion between tape 32 and forms 37 is of a lesser degree than thebond achieved between adhesive material 38, the form material, andsurface 21 respectively.

In practice the degree of adhesion measured on successful specimens hasbeen approximately as follows: Adhesion of underside of form, 20 ouncesper square inch; adhesion of underside of tape 32, 5 ounces per squareinch, using standardized steel test method. It will be apparent thatthese values are provided for illustrative purposes only and that othervalues or range of values may be chosen as long as there exists asufiicient difference in the degree of adhesion to cause separation ofthe form from its supporting tape before breaking the adhesive bondbetween the underside of the form and the layout surface or drawing.

Adhesion between the underside of the form and the protective releasepaper 33 has been determined at approximately one ounce per square inchfor the typical sample values indicated above.

FIGURE 9 shows a further alternative embodiment. Roll 41 carries only asingle tape material 42 which at its underside supports by adhesionthereto forms 43. The underside of forms 43 is coated for adhesion tolayout surface 21, but in this construction, the top surface of tape 42is impregnated or coated to have little adhesion with the coatedunderside of form 43. In this manner, forms 43 do not adhere to the topside of tape 42 during juxtaposition on the roll. The use of rolls asshown in FIGURE 9 is identical with the description applicable to roll31, FIGURE 6.

It will be apparent that the constructions and arrangements describedheretofore provide significant advantages. Complex shapes and contoursof forms are not distorted during handling, but such forms remain fullysupported during their transfer from the supply means to the finaldrafting or layout surface. Moreover, the above described meanscontribute greatly to producing improved printed circuit drawings andlast but not least, the use of such forms is greatly simplified andexpedited.

While there have been described and illustrated certain specificembodiments of the present invention and several alternativeconstructions, it will be apparent to those skilled in the art thatvarious further changes and modifications may be made therein withoutdeviating from the principle and intent of the present invention, whichshall be limited only by the scope of the appended claims.

What is claimed is:

1. Means for dispensing forms for printed circuit use or the like upon asurface to which the forms are adhesively aflixed comprising: stripmaterial; a plurality of forms spaced relative to one another andadhesively fastened with one side to one side of said strip material;the other side of said forms being provided with a layer of pressuresensitive adhesive coating, and the adhesive characteristic of saidcoating being of such character with respect to the adhesive bondfastening the forms to the strip material that when said other side of arespective form is brought in contact with the surface to which the formis to be aifixed and upon exerting relatively light pressure upon thearea of contact between said form and surface, said form will remainafiixed to said surface, yet will be released from said strip materialupon moving said strip material away from the area on the surface withwhich the form has been brought in contact.

2. Means for dispensing forms for printed circuit use or the like upon asurface to which the forms are adhesively aifixed comprising:transparent strip material; a plurality of forms spaced relative to oneanother; means adhesively holding the top side of said forms to one sideof said strip material; the underside of said forms being provided witha layer of pressure sensitive adhesive coating, and said coating beingof such character with respect to said means holding the forms to thestrip material that when the underside of a respective form is broughtin contact with the surface to which the form is to be affixed and uponexerting relatively light pressure upon the top side of said formthrough sa d strip, said form will remain affixed to said surface, yetwill be released from said strip material upon movingsaid strip materialaway from the area on the surface with which the form has been broughtin contact.

3. Means for dispensing forms for printed circuit use or the like upon asurface to which the forms are adhesively aifixed comprising: atransparent strip; the underside of said strip provided with a layer ofpressure sensitive adhesive coating; said coating adapted to supportindividual forms which adhere thereto with their respective top sides;the underside of each such form provided with a layer of pressuresensitive adhesive coating; and the bond between the underside of saidstrip and the top of said form being of such character that when theunderside of a respective form is brought in contact with the surface towhich it is to be aflixed and upon exerting relatively light pressureupon the top side of said form through said strip, the form remainsaffixed to said surface, yet will be released from said strip relativelyreadily upon moving said strip away from the area on the surface towhich the form has been affixed.

4. Means for dispensing forms for printed circuit use or the like upon asurface to which the forms are adhesively affixed comprising: a roll oftransparent tape material; the underside of said tape material beingprovided with a layer of pressure sensitive adhesive coating; saidcoating adapted to support individual forms which adhere thereto withtheir respective top sides; the underside of each such form providedwith a layer of pressure sensitive adhesive coating, and the bondbetween said tape and the top of each form being of such character thatwhen the underside of a respective form is brought in contact with thesurface to which the form is to be affixed and upon exerting relativelylight pressure upon the top side of said form through said transparenttape material, the form will'remain afi ixed to said surface yet will bereleased from said tape material relatively readily upon moving saidtape material away from the area of the surface to which the form hasbeen affixed.

5. Means for dispensing forms for printed circuit use or the like as setforth in claim 4 wherein a second tape material is provided to overlayon the adhesive coating of said forms for protecting said coating, andsaid second tape being a material with which the underside of said formsand coating thereon bonds to a lesser degree than the bond between thetop side of said respective forms and the underside of said transparenttape material and its coating.

References Cited in the file of this patent UNITED STATES PATENTS2,608,503 Meyer Aug. 26, 1952 2,805,183 Higgins Sept. 3, 1957 FOREIGNPATENTS 929,341 France Dec. 23, 1947

